ALGJE OB SEA-WEEDS. 161 



specimen as far up the river as Newington. Harvey describes 

 the frond as " from one to twelve inches broad, of no certain out- 

 line, lying flat on the surface of rocks or sand, unattached, or 

 fixed to Algge and Corallines by several points of its lower sur- 

 face, wholly composed of confervoid, articulated, anastomosing 

 filaments, and comparable either to a network with irregular 

 meshes, or to a skeleton leaf." The species of Enter omorpJia, 

 Viva, and Conferva, all of which extend far up the Parramatta 

 River, seem to be cosmopolitan, and so also do many of the 

 species of Cladoplwra ; but of the family of Siphonese, there are 

 some remarkable plants, which deserve more than a passing re- 

 mark. Of C odium, I have noticed three species C. tomentosum 

 (which also occurs in Europe), C. spongiosum, and C. mamillo- 

 sum (?). The fronds of Codium are sponge-like, being composed 

 of one-celled branching filaments filled with green matter, and 

 the fructification is minute, consisting of spore cases attached 

 laterally. Of the genus Caulerpa there are several species 

 figured by Harvey, but of these I have met with only two C. 

 hypnoides, and C. sedoides, for both of which I am indebted to Mrs. 

 Pearson. This genus derives its name from caulos, a stem, and 

 erpo, to creep, the creeping surculi being the characteristic of 

 the genus. C. liypnoides has the appearance of a Ilypnum, or 

 moss, and is said to bear a close resemblance to a Swiss fossil, 

 figured by Brongniart under the name Facoldes liypnoides. 



In bringing this communication to a close, I may remark that 

 the study of sea-weeds is attended with many collateral advan- 

 tages, for it is almost impossible to examine the forms and struc- 

 ture of them without being occasionally diverted to other studies. 

 Many beautiful zoophites will be frequently found adhering to 

 them, and hence the collector is imperceptibly led to the consi- 

 deration of matters beyond the range of the vegetable kingdom . 

 In my inquiries, trifling and limited as they have been, I have 

 noticed with much pleasure several species of Flustra and Ser- 

 tularia. These are interesting objects for the microscope, and the 

 study of them is calculated to give us a most extended view of 

 the Creator's works, for in a common specimen of Flustra, it has 

 been estimated that there are 18,000 polypi, 396,000 tentacula, 

 and 39,600,000 cilia on these tentacula ! " How much life and 

 active employment," says a late writer, " on a small polypidom". 

 v 



